Polymeric, microporous foams have been applied to various fabrics and have found use, for example, as barriers to the passage of liquids and microorganisms. Where such barriers are applied to "breatheable" materials, that is, materials which are porous enough to permit the free circulation of air or other gases, it is important that the application of the barrier does not adversely affect the air permeability of the material to which the barrier is applied. Applications include protective garments for hospital and industrial uses, hospital drapes, fabric wraps for surgical instruments, backings for medical tapes and wound dressings, diapers, feminine hygiene products, adult incontinence products, rainwear, rain covers and tarpaulins. In hospital and medical/surgical applications, in particular, the use of foam-coated fabrics prevents the passage of water and other liquids such as blood, while permitting free flow of air. Their use prevents contamination by microorganisms such as bacteria or viruses, which may be present in various physiological fluids.
Free flow of air is critical in the case of medical tapes or wound dressings. While it is essential that wounds be kept sterile by excluding microorganisms from the wound, air should be permitted to contact the wound in order to keep it dry and promote healing. Breatheable fabrics are also needed in protective garments, since use of fabrics which are not breatheable may result in the wearer's discomfort and inconvenience due to excessive perspiration, which cannot evaporate through the fabric by the circulation of air, unless the fabric is breatheable.
Foam-coated fabrics have achieved wide use because they are economical, comfortable, drapeable, nonlinting, heat-sealable, and sterilizable by steam, gas or gamma radiation. In addition, foam-coated fabrics can be made antistatic, antimicrobial, or flame retardant or can have other desirable properties imparted to them by appropriate treatment.
In U.S. Pat. No. 3,567,565, R. L. Jones et al. disclosed a laminate having increased strength and dimensional stability. The laminate consists of a foam laminated to a warp knitted fabric.
In U.S. Pat. No. 3,615,970, R. E. May disclosed foam-laminated glass fabrics, in which the latex which is foamed contains a flame retardant plasticizer.
In U.S. Pat. No. 4,499,139, W. E. Schortmann described the use of a froth sizing to establish a bacterial barrier in fabrics used in surgical gowns. The sizing is worked below the surface of the fabric and leaves the outer surface of the fabric froth-free.